In spite of many advances in liver transplant surgery, an increasing number of patients with terminal liver disease are dying while awaiting transplants. Consequently, further advances in the storage of donor livers, as well as alternative replacement options and mechanisms for supporting liver function while awaiting a donor liver are needed. A very promising area of research and development is in the development of engineered solutions to the problems of liver support for either natural donor organs or bioartificial livers. However, efforts undertaken within a single discipline are hampered by the complexity of both the engineering and biological aspects of such projects. This proposal constitutes a partnership between bioengineers, biologists and a liver transplant surgeon with the goal of combining their expertise to devise improved methods of liver support via bioartificial livers and improved preservation of donor livers via machine perfusion preservation (MPP). The partnership encompasses three inter-related projects. The first project focuses on delivery of oxygen and other nutrients to the cells in in vitro systems such as the bioartificial liver. The approach involves the modification of the support matrix to facilitate enhanced mass transport. The second project addresses the hypothesis that improved bioartificial liver function can be attained by providing a more physiological combination of cell types in the support device. Specifically, we will investigate the relationship between Kupffer cells and hepatocytes in maintaining prolonged hepatic-specific function in culture. The final project focuses on development of methods for optimization of microvascular perfusion in machine-perfused livers. This project uses a combination of intravital microscopy and mathematical modeling. In all of the projects, engineering and biological approaches, as well as clinical experience, are combined to address focused, clinically relevant problems. Moreover, the unique environment that supports the partnership will maximize the potential for success in this interdisciplinary approach and provide an avenue for potential clinical application of laboratory advances.